(a) Field of the Invention
The present invention relates to a golf club, specifically to a material of a head thereof.
(b) Description of Prior Art
In recent years, titanium or titanium alloy has come to be used for a material for a golf head, due to its light and comparatively strong property. Titanium or titanium alloy has been used as a material not only for an iron head or a putter head, but for a hollow metallic head of a wood club (so called metal wood). The light weight of titanium or titanium alloy enables the lightening of a head as well as the large-sizing thereof. A light head is easy to play with, while a large head has a larger sweet area, i.e., an area on a striking face in which a ball travels well and comparatively straight when struck thereon.
Conventional titanium alloy used for a material of a head, for example, is titanium-aluminum (Ti--Al) alloy, as described in Japanese Patent Un-Examined Publication No. 6-545. However, as titanium or titanium alloys have such a high melting point that they have been difficult to cast. For example, the melting point of titanium is about 1,700 degrees centigrade, while that of a Ti--Al alloy also is as high as between 1,500 and 1,600 degrees centigrade. Further, titanium, though it has a high stiffness, is comparatively fragile material, so that it has been liable to be damaged by the shocks developed in striking balls. Furthermore, it has been desired that a golf club head should have an improved strength and be further lightened, in order to be suited for various manners in which it is used.